Table of Contents Buoyancy


• 2 glasses • 1 ounce of oil • Ten objects that sink or float • String and a float for testing objects • Life jackets


Sailing Centers


Begin with Part II (if you are not familiar with the information in Part I), followed by Part III. The goal of this module will vary greatly due to the sailing level and content knowledge of your students. Start with the basics of what sinks and floats and build to weight distribution in the boat. If students are familiar introduce Center of Lateral Resistance, and Center of Effort. Relate pressure on the sails to the pressure pushing up on the boat from the water. Balancing the two combined with good weight distribution in the boat equals fast sailing. Have students apply the skills on the water by simply standing in the boat while it’s in the water a balancing it with their weight. For seasoned sailors have them adjust their position in the boat to keep the boat flat while sailing upwind or downwind.


Formal Classroom Settings


Begin with Part I. Keep in mind, students may have difficulty with the density equation. Continue with Part II, Part III, Part IV, on day 5 launch the designs and have a race. Remember to discuss which designs were successful and have students reflect on any changes they would make on their designs to make them more effective.


Career Connection


Marine Engineers work with buoyancy every day when they design ships and submarines. Divers and marine scientists that work with underwater exploration need to make sure they adjust and design their equipment to work properly according to the pressure at different depths. Ship captains transporting cargo must properly configure the weight of goods their ships can transport in salt and fresh water. Any miscalculations can cost shipping companies large amounts of money.


Background Knowledge


Buoyancy is the upward force exerted on an object by the surrounding fluid (in most cases water) in which the object is immersed. Buoyancy acts against the force of gravity.


If the density of an object is greater than that of the surrounding fluid, the object sinks. Density of Object > Surrounding Fluid = Object Sinks


If the densities are equal, the object is neutrally buoyant and hovers in the fluid. Density of Object = Surrounding Fluid = Hovers


If the density of the object is less than that of surrounding fluid, the object floats. Density of Object < Surrounding Fluid = Object Floats


Visit density and buoyancy Interactive Simulations at the University of Colorado to explore the density and buoyancy of a variety of objects and fluids. (http://phet.colorado.edu/en/simulation/buoyancy)


Density is defined as the mass per unit volume of an object. D=M/V. Remind students that mass is not the same as weight. Different fluids have different densities. Since oil is less dense than water, it floats on water.


34


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141